In compressed air/water snowmaking systems, two separate hoses are connected to each snowmaking gun and opening to the snowgun nozzle. One of the hoses contains water and the other contains compressed air. Typically, metal water and compressed air manifold pipes extend parallel to each other in the direction of the ski slope or trail, with those pipes either being exposed or beneath the ground. Typically, at longitudinally spaced positions along the respective pipes, water hydrants and air hydrants extend upwardly, such hydrants being typically of cast metal and being welded to the pipes with lower inlet ends opening to the interior of the water and compressed air manifold pipes. Such water and air hydrants include manual shutoff valves for controlling the flow between the inlet of the water and air hydrants and typically right angle outlets downstream of the shutoff valves. Flexible water hoses and air hoses are threaded to the hydrant outlets at one end and are connected to respective water and air inlets at the snowgun. When the snowgun is shut down, the water in the water hose must be drained to prevent freezing. In the past, this is typically done by manually disconnecting the end of the water hose at the water hydrant outlet and turning on the compressed air to pressurize the snowgun and to blow any water within the snow gun and the water hose backwards through the hose, which then exits at the hose end previously connected to the water hydrant outlet.
In the past, automatic snowmaking operations have primarily implemented tower mounted snowguns where the hose is mounted to always enable the water hose to drain by gravity. Automatic operations using land or sled mounted snowguns have required expensive multi-directional air valves to be installed in order to achieve the required blow-out of water hoses.
It is therefore a primary object of the present invention to provide a simple, automatic blow-out system for snow making guns to ensure automatically, upon shutoff of the water supply to a particular gun, the blow-out of the water retained within the water hose in the direction of the snowmaking nozzle of the snowgun, and in which the necessity for disconnecting the water hose at the water hydrant outlet is eliminated.
It is a further object of the present invention to provide an automatic blow-out system for snowmaking guns which utilizes a simple spring-loaded check valve connection between the water and air piping to the individual guns and restriction means within the air piping to accomplish automatic water hose blow-out through the snowmaking nozzle without power or complicated valving.